Increasingly, communication networks are using optical fiber links to interconnect switches, routers and multiplexer nodes of the networks. On each optical fiber link, Wavelength Division Multiplexing(WDM) is being used to increase bandwidth utilization of the optical fiber link. When a network includes many nodes, the blocking probability increases due to wavelength contention which occurs when two channels require the use of the same wavelength. This wavelength contention problem is often overcome by using wavelength conversion whereby one of the channels is converted to another unused wavelength. Wavelength conversion for WDM networks is described in the article entitled "Wavelength Conversion Technologies for WDM Network Applications" by S. J. B. Yoo, Journal of Lightwave Technology, Vol. 14, No. 6, Jun. 1, 1996.
One technique uses four wave mixing effects of a semiconductor optical amplifier to accomplish wavelength conversion. However, many of the existing wavelength conversion techniques require expensive components and/or are complicated to implement. Thus, there is a continuing need for a simple, low cost wavelength conversion apparatus.